Remove Collection, Collections and clean up List/Set/Queue implementations of retain/remove.

tools/dom/templates/immutable_list_mixin.darttemplate

Index: tools/dom/templates/immutable_list_mixin.darttemplate
diff --git a/tools/dom/templates/immutable_list_mixin.darttemplate b/tools/dom/templates/immutable_list_mixin.darttemplate
index 7376bc48fadec25daabddba5995c88d746d6050b..13980cbe00026b7b15a894090e4fb1054348106c 100644
--- a/tools/dom/templates/immutable_list_mixin.darttemplate
+++ b/tools/dom/templates/immutable_list_mixin.darttemplate
@@ -155,14 +155,6 @@ $endif
     throw new UnsupportedError("Cannot remove from immutable List.");
   }
 
-  void removeAll(Iterable elements) {
-    throw new UnsupportedError("Cannot remove from immutable List.");
-  }
-
-  void retainAll(Iterable elements) {
-    throw new UnsupportedError("Cannot remove from immutable List.");
-  }
-
   void removeWhere(bool test($E element)) {
     throw new UnsupportedError("Cannot remove from immutable List.");
   }